Multiple wheel grinding machine



June 5, 1956 A. J. ST. GEORGE MULTIPLE WHEEL. GRINDING MACHINE.

Filed March 51, 1954 INVENTOR. lfrecl I. 5%. George TTORNEY BY ClQ m L.

United States Patent '0 MULTIPLE WHEEL GRINDING MACHINE Alfred J. St.George, Manchaug, Mass.

Application March 31, 1954, Serial No. 419,973

1 Claim. (Cl. 51--95) This invention relates to grinding machines, andmore particularly to a machine in which different types of grindingwheel may be alternatively and selectively employed to grind a singlework piece.

It is commonly desirable to rough grind a work piece by a coarse wheeland then to finish it in a subsequent operation by means of a wheel offiner abrasive grain or other different structure. The standard grindingmachines are for grinding external or internal cylindrical surfaces orplane surfaces in which a given work piece and the abrasive wheel aremoved relatively while the abrading action proceeds. When the work piecehas been finished, such as in a rough grinding operation which bringsthe work to substantially the desired size, it must be removed from itssupports and laid aside for a subsequent abrasive finishing step. Thatprocedure may be satisfactory for grinding a large quantity of duplicatework pieces, but it is often desirable to rough grind and then finish asingle work piece, without facing the problems inherent in changing thegrinding wheel or rernounting the work on another machine.

A primary object of my invention is to provide a grinding machine ofthis general class with a plurality of abrasive wheels so mounted thatany wheel may be quickly brought into a duplicable operativerelationship to the work piece without disturbing the setting of thework.

A further object is to provide a grinding machine in which separatelydriven grinding wheels are so mounted that any wheel may be quicklymoved into a correct grinding relationship with a work piece, andwherein each wheel may be fed laterally toward the work with precisionby the same wheel feed mechanism.

A further object is to provide a machine of this class wherein thewheels are mounted on a rotatable turret and the power drive is socoordinated with the turret and wheels that only the wheel to be used isautomatically supplied with power, and wherein the turret may beoperatively fixed only in a position which insures that the selectedwheel is accurately located for its grinding operation. Further objectswill be apparent in the following disclosure.

Referring to the drawings:

Fig. 1 is a top plan view of the machine, with parts omitted for clarityof illustration;

Fig. 2 is a fragmentary front vertical elevation, with parts in section;

Fig. 3 is a vertical transverse section, partly broken away; and

Fig. 4 is a simplified wiring diagram of the machine.

In the drawings, I have illustrated my multiple wheel turret inassociation with a cylindrical grinding machine, but this turret mayalso serve in other grinding machines, such as one employed for grindinginternal cylinders or flat or other shaped surfaces. In the machineillustrated, a round work piece W is suitably mounted for positiverotation on work supports and table which may be of standardconstruction and operation, "such as is shown in the U. S. patent toNorton No. 762,838 of 2,748,540 Patented June 5, 195 6 June 14, 1904, orsubsequent improvements thereof relating to cylindrical grindingmachines. The cylindrical work piece may be supported on a centering pincarried by a suitable headstock 10 and a further pin carried, by

the tailstock 11. The work is suitably rotated, as by a dog on theheadstock spindle driven by an electric motor 12, as is understood inthe art. This work piece may be reciprocated relative to the abrasivewheel by suitable mechanism, such as a table 13 mounted on V and flatways 14 and 15 and driven by reversing gear mechanism engaging the rack16 fixed on the table, as is shown in the patent, so that a long piecemay be properly presented to the grinding wheel. If the grindingoperation is what is known as surface grinding and the work is a flatpiece mounted on a reciprocating table, this construction may be of thegeneral type shown in the U. S. patent to Norton #1,l08,779 of August25, 1914, and later modifications thereof, wherein a wheel is adjustablymovable laterally over the work table. Similarly, an internal grindermay conform with the principles and construction disclosed in the U. S.patent to Taylor #1,805,056 of May 12, 1931, and related patents orlater modifications thereof, such as a machine having the work mountedon a bridge over a reciprocating table carrying the grinding wheel.

The primary feature of this invention involves the use of a plurality ofgrinding wheels, such as a coarse abrasive wheel 20 and a fine abrasiveor finishing wheel 21, which are rotatably mounted on horizontalspindles or axles in bearing supports of desired construction carried ona revolvable vertical axis turret 22. The wheel 20, which may be drivenby an electric motor attached directly to its axle, is shown as mountedon a support 23 on the turret and power driven by a constant speedelectric motor 25 of suitable characteristics mounted on the turret andhaving its pulley axially parallel with and belt connected to thegrinding wheel axle. Similarly, the other wheel 21 carried by the mount27 on the turret has its spindle driven by a belt from the motor 28carried on the turret. In the form illustrated, each abrasive wheel isintended to be used in a position where the line of grinding c011- tactwith the work is axially parallel with the work axis. The grindingwheels are so mounted on the turret in a definite angular displacementthat their operative faces or lines of contact with the work areequi-distant from the vertical axis about which the turret is revolvedand each wheel may be positioned exactly relative to the work byrotation of the table and adjustment of the Wheel feed mechanism. Theturret is so constructed and the wheels are so located that the wheelsmay be brought readily into the same grinding position withoutinterference with other parts of the machine. That is, the turret ismounted on bearings, ways or a centering device so arranged that theturret may be revolved in either direction for. the selectiveorientation of a wheel.

In order that the grinding wheels may be moved precisely towards andfrom a work grinding position, the turret 22 is carried on a slide 30which is slidably mounted on the base 31. The turret and the slide 30are each preferably provided with an arcuate or a circular slideway 34shaped as horizontal plane surfaces mounted in sliding contact so thatthe turret may slidably revolve about an axis perpendicular to andconcentric with the slideways 34 so as to present the selected wheel inan operative grinding position. The turret may be axially located on theslide 30 by a vertical center pin 36 which has a large fiat head fittingwithin a circular recess in the top of the turret.

The turret is releasably secured to the slide and may be held in a rigidposition for a grinding operation by threads on the lower end of thecenter pin 36 for receiving a nut 37 which bears against a plane face onthe under side 3 of the relatively stationary wheel slide 30. This nutis pinned to the slide or prevented from turning by shoulders of arecess 38 in the slide within which the nut is located. The center pin36 may be turnedrelativeto the nut 37 by means of a hex nut 38 securedto the top of the pin and turned suitably by a socket wrench removablyor fixedly applied thereto, or by other suitable mechanism. Thus, torevolve the turret, the nut 37 is released from clamping engagement withthe bottom of the slide, and when properly positioned the turret may beagain clamped to the slide.

In order that the rotary turret 22 may be accurately positioned so thatthe line of contact of the grinding wheel with the work may be axiallyparallel with the work piece W, the under side of the turret is providedwith accurately shaped vertical cylindrical or tapered holes 40 (Fig. 2)opening downwardly and preferably so located that they intersect thecircular plane of the slideway 34 where the turret 22 bears precisely onthe slide. There is one hole 40 for each wheel on the turret. The turretsupport or slide 30 has one vertical cylindrical hole therein alignedwith a hole 40 and arranged to carry a slidable cylindrical plug 42. Thehole in the slide 30 is deep enough so that the plug 42 may ridedownwardly and move entirely out of the hole 40 in the turret or may bethrust upwardly into that turret hole. The plug 42 and the walls of theholes in the turret and the slide are accurately shaped for interfittingslidably. The plug 42 may have its upper end tapered so as to aid itsentry into the hole 40 for positioning the turret. This plug 42 may bemoved vertically by means of a crank arm 44 which is shaped as a pinmounted eccentrically on a rotatable horizontal cylindrical body 45mounted in a suitable horizontal bearing socket in the slide. The pin 44rides in an elongated groove in the side of the vertical pin 42, and theparts are so shaped that this pin may contact with the lower face of thegroove to draw the pin downwardly and when rotated to an upper positionto force the pin upwardly. The rotatable body 45 may be rotated by meansof a crank arm 48 suitably attached to the body 45 and projectingoutwardly from the slide. If the wheels are mounted at 180 apart, asregards the centers of their grinding lines of contact with the work,the holes 40 are likewise 180 apart and so located that when the lockingpin 42 fits in one turret socket 40, the associated wheel will bepositioned exactly for the grinding operation, and each wheel will bethus locked in the same exact angular position as are the other wheelswhen engaging the work. This lock insures that the turret cannot bemisplaced, and it must be locked only for grinding. If three wheels aremounted at angular displacements of 120, then the holes 40 will likewisebe 120 apart, so that the turret may be locked only in those positionswhich provide for one wheel grinding the work.

The turret assembly comprising the lower relatively stationary slide 30is mounted for a sliding movement perpendicular to the work piece. Theturret base 31, which may be integral with or separate from the worktable supporting base, is provided with an upwardly projecting slideway,such as the dove-tailed slideway 50. The wheel slide 30 has a slidewaywhich, with the aid of a standard adjustment gib 51, serves to interfitwith the stationary slideway 59 of the base. This wheel slide may beprecisely adjusted relative to the work by a standard wheel feedmechanism comprising a half nut 52 fixedly projecting downwardly fromthe bottom of the wheel slide and engaging the thread of the wheel feedscrew 54 which is interconnected with a suitable manually operated wheelfeed mechanism 55, such as is shown in the U. 5. Patent to Norton#762,838 and later constructions of this type used in the industry.Hence the operating grinding wheel may be fed toward the work axis byproper manipulation of the hand wheel mechanism. The connections to thescrew 54 pass through the work base to a position where the operator maywatch the grinding operation and suitably adjust the position of thegrinding wheel. It will be observed that the wheels are so located onthe turret that they may be revolved into a grinding position withoutinterference with other parts of the machine, so that it is merelynecessary to feed the wheel rearwardly only enough to clear the workwhen a second wheel is to be used. In a plane surface grinding machine,the wheel is raised for such clearance, and in a machine for grinding aninternal cylindrical surface, the wheel may be fed laterally for thepurpose.

It will be understood that the turret construction and mounting arenecessarily coordinated with the other features of the selected type ofmachine, such as mounting the turret on the reciprocable table of aninternal grinder in a position where each wheel may be broughtaccurately into a grinding position by revolving the turret. In thatcase, a secondary cross slide as above described may carry the turretand be mounted on the table for a transverse wheel feeding movement, orthe turret base and slide as herein described may be employed with thework mounted on a reciprocable table. Also, I may employ variousaccessory devices, such as a suitable water circulating system indicatedgenerally by the pipe 58 and pump 59 connecting a tank supply of fluidwith the grinding zone. A wheel guard and other protective devicesassociated with the grinding wheel, as well as a wheel truing mechanism,may be employed and need not be illustrated.

The grinding wheels are so interconnected in an electrical power systemthat each wheel is rotated in the same angular direction when in contactwith the work and only the wheel adjacent the work is rotated, while theother wheels remain inoperative and stationary. The power supply may betransmitted to the operative wheel through sliding contact membersmounted respectively on the turret and base and preferably throughspring pressed switches associated with the wheels and operatedautomatically in such a manner that only the front wheel may be rotated.A suitable power system for a two wheel machine, as shown in Fig. 4,comprises the main power line 60 connected through manually operatedpush button switches for starting and stopping the wheel, as Well as thework movement. This may comprise a normally closed switch 61 which maybe operated by a push button to serve as a stop switch. One line goesthrough a manually operated, normally open micro-switch 62 to the motor25. The power line also connects to the other motor 28 through anormally open push button switch 63 and the normally closed stop switch61, as illustrated. A normally open micro-switch 64 is interposed in theline to the motor 25 and another normally open micro-switch 65 islocated in the line to the motor 28. These switches 64 and 65 ofstandard construction are so located on the wheel slide below the turretin a definite relation to the associated grinding wheel that when theturret has been moved around to an exact position for one of the wheelsto contact with the work as is defined by the locking plunger 42, thenthe spring pressed contact 66 (Fig. 3) of the micro-switch 64, or switch65, is struck and moved downwardly by a cam 68 to maintain the circuitclosed. The cam has a beveled face and it is so mounted on a projectingangle plate 69 fixed on the turret that the cam will strike the switchcontact member 66 and hold it down to close the normally open switch andthus insure that the current will feed to the wheel whose associatedswitch is under that cam 68. The other normally open micro-switchassociated with the second wheel, such as switch 65 of wheel 28, willremain open because there is only one cam member 68 on the turret. Theswitch 65 is located and arranged relative to its wheel 28 as is switch64 shown in Fig. 3. The two micro-switches 64 and 65 are mounted on thewheel slide at apart relative to the turret rotation, so that when theturret is rotated from a first position of closing switch 64 to a secondposition 180 from the first and there locked in place by the slidinglock 4-2, then the cam 68 will close the other switch 65 and theassociated wheel will be rotated accordingly. The main power line 60 maycomprise cables that are fixed inside the base 31 and passed upwardly toconnect with the switch members on the turret. To prevent the cable frombeing twisted seriously by rotation of the turret always in onedirection and to avoid the use of sliding electrical contacts, Ipreferably provide a pair of associated stop members 70 and 71 (Fig. 1)mounted respectively on the wheel slide and the turret and so arrangedthat the turret may revolve in one direction only as far as is permittedby the contacting of the stop members, so that the turret must berotated in the opposite direction to bring the other wheel into anoperative position.

It will now be apparent that various types of grinding machines may besuitably modified to provide multiple wheel turrets and that equivalentconstructions may be substituted for those herein described. Hence theabove disclosure is to be interpreted as setting forth the principles ofthe invention and a preferred embodiment thereof and not as imposinglimitations on the appended claim.

I claim:

A grinding machine comprising a base having longitudinal slideways, awork table slidably mounted thereon, said base having transverseslideways, a wheel slide mounted on the transverse ways for movementtowards and from the work table, precision mechanism for moving thewheel slide on its ways, a revolvable turret on the slide, said turretand wheel slide having horizontal interfitting arcuate slideways forrevolution of the turret about a vertical axis, means including avertical center pin which locates the turret and releasably secures itrigidly on the slide, a plurality of rotatable grinding Wheels, meansincluding horizontal spindles for the Wheels which locate the wheels ina definite radial angular displacement on the turret for alternativelygrinding a work piece in the same position on the work table, lockingmeans including a positioning member on the turret associated with eachwheel and a single lock on the slide for locking the turret againstrevolution on the slide and positioning any selected wheel only in thesame exact angular position relative to the work table, a separateelectric motor connected to each axle for driving the associated wheel,a power circuit, and means including switches positioned on the slide ina definite relationship to the wheels and a single actuator thereforlocated on and moved by the turret for selectively interconnecting thepower circuit only with the motor which is connected to rotate the wheelopposed to the work table.

References Cited in the file of this patent UNITED STATES PATENTS946,989 Steinle Jan. 8, 1910 1,150,222 Norton Aug. 17, 1915 1,528,188Frost Mar. 3, 1925 1,933,872 Olson Nov. 7, 1933 2,423,367 Bolender July1, 1947 FOREIGN PATENTS 8,091 Great Britain Mar. 31, 1911 22,457 GreatBritain Oct. 2, 1912 243,826 Germany Feb. 23, 1912 862,129 France l Nov.22, 1940

